1. Field of the Invention
This invention relates to polycarbonate resins and more particularly to polycarbonate resins based on sulfur containing phenolic compounds.
2. Description of the Prior Art
Polycarbonates derived from reactions involving dihydroxy compounds and carbonic acid derivatives have found extensive commercial application because of their excellent mechanical and physical properties. These thermoplastic polymers are particularly suited for the manufacture of molded article products requiring impact strength, rigidity, toughness, thermal and dimensional stability as well as excellent electrical properties.
When a polycarbonate article is to be used in above ambient temperature environments, it is necessary that the polycarbonate be adapted to have proper physical properties at these temperatures. For example, polycarbonates have found extensive use in automotive applications due to their light weight in relation to their strength characteristics. When a polycarbonate is used in such applications, it must retain its dimensional stability during manufacture of the automobile. Particularly, the polycarbonate must retain its dimensional stability in a paint oven or during similar high temperature processing of the vehicle.
Further, polycarbonates have been found useful in the appliance industry, for example in industrial power tool housings and similar applications where the tool and, hence the polycarbonate, are required to withstand continuous use at elevated temperatures.
Further, in some applications polycarbonates are required to be subjected to increased temperatures over their entire service life and, further, in high humidity environments.
Accordingly, in order to provide this dimensional stability at elevated temperatures and in humid atmospheres, in accordance with the present invention, a polycarbonate is provided which has improved dimensional stability at elevated temperatures and after aging at high temperature and humidity.